Glia maturation factor is a protein factor found in the adult brain that has the ability to enhance the phenotypic expression of normal immature astrocytes in culture. In the proposed work experiments are planned to test the effect of the factor on various neoplastic glial cells. Both morphological, biological and chemical parameters will be used to measure the effect. We try to find out if the factor blocks the appearance of some of the neoplastic properties of the cells in an otherwise permissive environment. It is hoped that the study will provide some insight into the interaction between the maturation factor and the malignant process.